Recently, an antenna for realizing functions, such as near field communication (NFC), wireless power charging (WPC), and magnetic secure transmission (MST), is being installed in mobile devices such as a mobile phone, a tablet PC, and a notebook PC. However, other metallic parts are present in such mobile devices and an eddy current occurs when an alternating magnetic field formed in the device is applied to such metallic parts, which results in degradation in performance of the antenna and reduction in a recognition distance.
Conventionally, in order to solve the above problems, an antenna device with multiple uses was prepared by attaching a high permeability ferrite sheet to one side of a typical circuit board (antenna), such as a polyimide substrate, having an antenna pattern layer formed on the other side thereof. This uses a principle that a magnetic body, such as the ferrite sheet, focuses the magnetic flux of the antenna so that the penetration of a magnetic field into a metal surface and the generation of the eddy current may be prevented and operating characteristics may be improved.